Rollup merge of rust-lang#149549 - Jamesbarford:chore/regression-test-ttbr0_el2, r=WaffleLapkin

Regression test for system register `ttbr0_el2`

Regression test for recognising the `ttbr0_el2` register.

closes rust-lang#97724

Author: matthiaskrgr

tests/ui/asm/aarch64/ttbr0_el2.rs

@@ -0,0 +1,11 @@
+//! Regression test for #97724, recognising ttbr0_el2 as a valid armv8 system register
+//@ only-aarch64
+//@ build-pass
+use std::arch::asm;
+
+static PT: [u64; 512] = [0; 512];
+fn main() {
+    unsafe {
+        asm!("msr ttbr0_el2, {pt}", pt = in(reg) &PT as *const _ );
+    }
+}